In these cases, it is not the main credit card companies that are causing these issue, instead, it is mainly the back end payment processors who will facilitate a credit card transaction. For example, Stripe has a history of dropping many people, including numerous content creators, artists, and various donationware companies, e.g., electronics companies like Apple, pressuring a payment processor to ban a developer who is using them to accept donations for a board view applications tailored to 3rd party repair of products made by those companies. Since nothing they are doing is illegal, they can't get the software banned, thus they go after income sources instead.
Anyway what collective shout did is just the beginning, and given how fast steam and itch gave in, they will now double down. Bit by bit they will chip away at what content in allowed, until itch will ban everything more violent than Mario Cart.
Keep in mind that collective shout tried to use a different method to get the game Detroit: Become Human banned, though that was before they utilized the payment processor route.
The censorship groups of the past that tried to ban things like Dungeons And Dragons, Magic: The Gathering, and many other things,never fully disappeared, and the success of collective shout, will effectively give them all a roadmap to exploit.
If there is no resistance to this, then eventually every prude will effectively have veto authority on all content on itch, steam, and many other platforms.